The present invention relates to a tiltable steering shaft assembly for automotive vehicles, and more particularly to an improvement of a fastening device for a tiltable steering shaft assembly of the type in which when shifted into a remote position upwardly from a pre-selected angular position, the steering wheel is automatically returned to the pre-selected angular position and locked at the same position only by depression of the steering wheel.
In U.S. Pat. No. 4,102,218 issued on July 25, 1978, a fastening device for a tiltable steering shaft assembly has been proposed which comprises a stationary bracket mounted on the vehicle body structure for supporting the shaft assembly in place at a predetermined angle, a movable bracket secured to a tubular housing and pivoted to the stationary bracket for angular adjustment of a tiltable steering shaft journalled within the tubular housing, a toothed portion in the form of a sector gear integral with a free end of the movable bracket, a latch member pivoted to a side portion of the stationary bracket to be engaged with the toothed portion of the movable bracket in a locked position, a manual lever pivoted to the stationary bracket and cooperable with the latch member to move it toward an unlocked position, an engaging element provided on the manual lever and in engagement with the latch member to hold it in the locked position when the manual lever is released, and a spring for biasing the manual lever to maintain it in its released position. In use of the tiltable steering shaft assembly, it is advantageous that the angular position of the steering wheel can be adjusted step-wise to a desired angular position in such a way as to give a click feeling to the driver. It has, however, been needed to adjust the steering wheel to the desired angular position at each time after being shifted into a remote position upwardly with respect to the desired angular position to facilitate entry and exit of the driver into and out of the vehicle compartment.
For the purpose of eliminating such an inconvenience in use as described, in Japanese Utility Model Early Publication No. 58-30570, there has been proposed an improvement of the fastening device for the tiltable steering shaft assembly in which when shifted into a remote position upwardly from a pre-selected angular position, the steering wheel is automatically returned to the pre-selected angular position and locked at the same position only by depression of the steering wheel. The improved fastening device comprises a first manual lever arranged to release a lock of the fastening device for permitting upward movement of the steering wheel to the remote position, and a second manual lever arranged to readjust the pre-selected angular position of the steering wheel in accordance with the driver's physique. In use of the fastening device, it has, however, been experienced that during the process of readjusting the pre-selected angular position of the steering wheel, the second manual lever has to be operated in relation to operation of the first manual lever in a complicated manner.